Drawing instrument



S. HOFFMAN, J. SCHWARTZ, AND I. HOLDEN.

DRAWING INSTRUMENT.

' APPLICATION FILED II AII. 28, 1am.

.1 40 3 I Patented Feb. 14, 1922.

WITNESSES a INVENTORS SHMUEL HoFF/ m/v 1 (/OSEDH Scuwaerz- I A TTOH/VE Y8 UNITED STATES PATENT OFFICE.

SAMUEL HOFFMAIT, JOSEPH SCHWARTZ, AND ISIDORE HOLDEN, OF NEW YORK, N. Y,

DRAWING INSTRUMENT.

Specification of Letters Patent. Patent d F 14 1 2 Application filed march 28, 1921. SerialNo. 456,393.

' To all whom it may concern:

Be it known that we, SAMUEL HOFFMAN, Josnrrr SCHWARTZ, and IsIDonE HOLDEN, all citizens of the United States, and residents of the city of New York, borough of The Bronx, in the county of Bronx and State of New York, have invented a new and useful Drawing Instrument, of which the following is a full, clear, and exact description.

This invention relates to drawing instruments, and particularly to what is commonly known as an ellipsograph, and has for an object to provide a construction wherein by a quick adjustment different forms of ellipses may be drawn.

Another object of the invention is to provide an ellipsograph wherein a quick adjustment may be provided which will cause a variation in the length of the minor axis without affecting the length of the major axis.

Another object, more specifically, is the provision of an ellipsograph formed on the general principles of a compass with an adjustable guide arranged to guide the scribing' member for producing ellipses of difi'erent sizes and shapes. In the accompanyingdrawing Figure 1 is a longitudinal vertical section through an ellipsograph embodying'the invention, the same being taken approximately on line 1--1 of Fig. 2.

Figure 2 is a top plan view of the ellipsograph shown in Figure 1.

Figure 3 is a view similar to Figure 1, but showing the instrument adjusted for producing an ellipse having a different minor axis from the ellipse produced by the arrangement of parts shown in Figure 1. Figure 4" is a top plan view of the ellipraph shownin Figure 3. I

Iieferring ,to the accompanying drawing by numerals, 1 indicates a base plate, pref-- into a round extension 7 having a pin 8 on which a rotatable sleeve 9 is mounted, said.

sleeve having an arm 10 slidingly fitting into a tubular member 11 rigidly secured to a vertically positioned bar 12'pr0vided with graduations 13. A spring 14 is connected with 'bar 12 near the sleeve or tubular member 11 to the rounded extension 7 reduced extension 17 surrounded by a spring v 18v which bears against a clamping screw 19 and against the shoulder 20; The reduced extension 17 is slidingly mounted in a bore 21 in link 15 so that the spring 18 will continually tend to hold the lead or other marking member 22 against the surface to be marked, said lead being rigidly clamped in member 17 by the screw 19.

As shown in Figure 2 the guiding ring 14 is formed as a circular member and when arranged at right angles to the body 5, as shown in Figure 1, causes the marking member 22 to produce a true circle. If it should be desired to make this circle slightly elliptical the ring 14 is tilted slightly. In case an ellipse having a much longer major axis than a minor axis is desired, the ring 14 is tilted at an appreciable angle as shown in Figures 3 and 4. In order to guide, or rather in order to assist in determining the amount of tilting of the ring 14 graduations 13 are provided on bar 12 and the upper edge of the ring 14 is caused to register with any of the marks on this graduation according to the particular ellipse desired. In order to allow for this movement the ring 14 is provided with a central bar 24 to which it is rigidly secured, said bar being formed of. T-shaped material as shown in Figure 1, and the set screws so as-to clamp the bar in whatever position desired, as for instance, the position shown in Figure 3. It will be noted that the major axis of an ellipse cannot be varied but the minor axis may be changed readily as may be desired. p

In case the two ellipses are made close together and of the same size, spur 2 may be located properly for the first ellipse and then the screws 25 and 26 loosened slightly to allow the ring 14' to be moved in a direction longitudinally of the bar 24. WVhere this movement is very small, as for instance,

a sixteenth or eighth of an inch the second ellipse will be properly positioned to co-act with the first ellipse though if the second thereof in respect to the standard.

ellipse is to be made an appreciable distance from the first. it is preferable to move the entire instrument over to the major axis otthe second ellipse.

'hat we claim is 1. An ellipsograph comprisin'g'a standard. a scribing member I carried by the standard adapted to move around the standard. a ring for guiding said scribing memher. a bar rigidly connected with the ring and slidingrly fitted in said standard, and a pair of clamping screws fonclamping the bar in diii'erent positions whereby when said bar is moved longitudinally and bolted so that more of the ring will be on one side of the standard than the other andwhen the major portion of the ring is inclined downwardly a substantially true ellipse will be produced with the minor axis in proportlon to the angle of said bar and the position 2. An ellipsograph comprising a standard, a scribing instrument connected with the standard and adapted to move around the standard, the scribing instrument provided with a series of graduations, a. ring; carried by the standard, and means for adjustably clamping the ring to the standard so that the ring may be titled from a horizontal and moved more on one side of the standard than the other, said tilting; movement being determined by the graduations on said scribing instrument, said graduations determining the size of the major axis of the ellipse to be moved.

SAMUEL HOFFMAN. JOSEPH SCHWARTZ. ISIDORE -HOLDEN. 

